diff --git a/src/app_controller.py b/src/app_controller.py
index 88d58e3a..2a426b33 100644
--- a/src/app_controller.py
+++ b/src/app_controller.py
@@ -1489,10 +1489,8 @@ class AppController:
     else:
      self._set_rag_status("ready")
    except Exception as e:
-    import traceback as _tb_investigate
     self._set_rag_status(f"error: {e}")
-    sys.stderr.write(f"[RAG_INVESTIGATE] exception type={type(e).__name__}, module={type(e).__module__}, str={str(e)!r}\n")
-    sys.stderr.write(f"[RAG_INVESTIGATE] traceback:\n{_tb_investigate.format_exc()}\n")
+    sys.stderr.write(f"[DEBUG RAG] Failed to sync engine: {e}\n")
     sys.stderr.flush()
    with self._rag_sync_lock:
     if not self._rag_sync_dirty: